To make such a potion is fairly simple. Just make your usual hot chocolate. I prefer the powdered variety, because then you can make it extra-strong. Then dissolve a few caffeine pills in it. They're relatively tasteless, and the chocolate will drown out any bitterness.

You -could- also do this with coffee, but some of us find coffee to be vile tasting stuff, and the sugar from the chocolate also helps maintain that insane twitching that you'll experience from all that neat stuff coursing through your veins.